The present invention relates to an apparatus for collecting and purifying refrigerant in air conditioning systems, in particular, but not exclusively, for vehicles.
During the normal operation of the air conditioning systems the refrigerant is contaminated by: lubrication oil of the refrigerant circuit compressor, air or other incondensable gas, water and solid particles.
Although the contamination from oil is xe2x80x9cphysiologicxe2x80x9d, the other types of contamination are due mainly to undesired effects, such as:
inlet of contaminated refrigerant when loading the circuit, owing either to not pure starting refrigerant or to refrigerant stored in not enough clean reservoirs;
defects that cause infiltrations of air, through micro-cracks, in the low pressure branch of the circuit.
other contamination during the loading step of the circuit or during maintenance.
The presence of air and oil in the refrigerant affects unavoidably the correct operation of the conditioning system, reducing its efficiency, whereas the presence of water in the circuit generates acid substances that can damage the circuit same. It is necessary, therefore, to provide systematic maintenance for restoring the correct characteristics of the fluid.
Presently, the maintenance of the air conditioning systems entails periodically emptying the circuit and collecting the refrigerant after that it has been purified.
To this end, apparatus are provided that comprise, usually, an evaporator formed by a container having in the upper part an inlet for the mixture refrigerant/impurities and in the lower part an outlet for disposing of the impurities gathered on the bottom.
The separation of the impurities from the refrigerant is made through a distillation step by means of progressive evaporation of the refrigerant; since the impurities have a temperature of evaporation higher than the refrigerant, they deposit on the bottom.
Therefore, such apparatus comprise means that heat the refrigerant up to evaporation. The means for heating can be, for example, either a coil tube inserted in the evaporator and directly in contact with the mixture refrigerant/impurities, or an external heating jacket.
In both cases, it is possible to use the refrigerant same as heating medium. After the distillation, in fact, the fluid is compressed, thus reaching a temperature higher than before the distillation. Then, the fluid compressed and heated passes through the heat exchanger for the evaporation of the fluid not yet distilled.
An example of apparatus of this type is described in U.S. Pat. No. 6,263,695 in the name of the same applicant.
During the depuration, furthermore, the fluid entrains oil from the compressor, used for priming the refrigerant by rising its internal energy with respect to the starting condition. Therefore, it is necessary to provide a separator downstream of the compressor capable of collecting the oil from the refrigerant before that the latter is stored in a reservoir.
In order to carry out the whole refrigerant depuration process, firstly, two containers are necessary, one for the evaporator and one for the oil separator. Furthermore many ducts, pipe fittings, valves are necessary for directing the refrigerant through the purification circuit, according to a predetermined layout.
When assembling the apparatus, finally, it is necessary to carefully combine the different components to avoid leakages. However, owing to the high number of fittings:
the assembling and testing steps are time consuming;
the risk of defects in the apparatus is high.
It is object of the present invention to provide an apparatus for collecting and purifying the refrigerant of air conditioning systems in which the assembling and testing steps are much quicker and easier than in the prior art.
It is another object of the present invention to provide an apparatus for collecting and purifying the refrigerant of air conditioning systems that achieves a better quality and reduces the risk of leakage.
It is a further object of the present invention to provide an apparatus for collecting and purifying the refrigerant of air conditioning systems that is less bulky than in the prior art.
It is still another object of the present invention to provide such an apparatus where the containers for the evaporator and for the oil separator are made in a simple, quick and not much expensive way.
These and other objects are achieved by the apparatus according to the invention for collecting and purifying the refrigerant of air conditioning systems comprising:
a first tubular body defining the container of the evaporator, in which both the evaporation of the refrigerant coming from the conditioning system and the separation from the impurities take place;
a second tubular body in which the separation takes place between the refrigerant and the oil downstream of the compressor;
a heat exchanger in said first tubular body to cause the evaporation of said refrigerant;
characterised in that a top distribution flange and a bottom distribution flange are provided that keep together said first and second tubular body and close their open ends, ducts and valves being provided for making an hydraulic depuration circuit that comprises said first and second tubular body.
Advantageously, the collected refrigerant to purify is put into the apparatus and circulated through a plurality of ducts made directly in the distribution flanges. Therefore, the number of ducts and of fittings necessary is remarkably less than in the prior art, and then the risk decreases of having leakages during the start-up and operation of the apparatus.
In particular, the reduction of the number of fittings and of ducts necessary for the circuit results in a considerable simplification both of the assembling and of the testing step of the apparatus, with considerable time saving and with less possibility of errors when assembling.
Advantageously, in the bottom distribution flange at least a channel is made directly under the first tubular body used as separator/evaporator. In said channel the warm fluid flows coming from the compressor and going into the exchanger, whereby all the metal base of the evaporator is heated for conductivity. Therefore, the heat exchange surface used is large for all the duration of the evaporation of the refrigerant, independently from the height of fluid contained in the first tubular body, in order to provide a high rate of refrigerant collected and purified.